Miguel Goulão

Domain-Specific Languages (DSLs) are claimed to bring important productivity improvements to developers,
when compared to General-Purpose Languages (GPLs). The increased Usability is regarded as one of the key benefits of DSLs when compared to GPLs, and has an important impact on the achieved productivity of the DSL users. So, it is essential to build in good usability while developing the DSL. The purpose of this proposal is to contribute to the systematic activity of Software Language Engineering by focusing on the
issue of the Usability evaluation of DSLs. Usability evaluation is often skipped, relaxed, or at least omitted from papers reporting development of DSLs. We argue that a systematic approach based on User Interface experimental validation techniques should be used to assess the impact of new DSLs. For that purpose, we propose to merge common Usability evaluation processes with the DSL development process. In order to provide reliable metrics and tools we should reuse and identify good practices that exist in Human-Computer
Interaction community.

The usability of requirements engineering (RE) techniques has been recognised as a key factor for their successful adoption by industry. RE techniques must be accessible to stakeholders with different backgrounds, so they can be empowered to effectively and efficiently contribute to building successful systems. When selecting an appropriate requirements engineering technique for a given context, one should consider the usability supported by each of the candidate techniques. The first step towards achieving this goal is to gather the best evidence available on the usability of RE approaches by performing a systematic literature review, to answer one research question: How is the usability of requirements engineering techniques and tools addressed? We systematically review articles published in the Requirements Engineering Journal, one of the main sources for mature work in RE, to motivate a research roadmap to make RE approaches more accessible to stakeholders with different backgrounds.

The i* community has published guidelines, including model layout guidelines, for the construction of models. Our goal is to evaluate the effect of the layout guidelines on the i* novice stakeholders’ ability to understand and review i* models. We conducted a quasi-experiment where participants were given two understanding and two reviewing tasks. Both tasks involved a model with a bad layout and another model following the i* layout guidelines. We evaluated the impact of layouts by combining the success level in those tasks and the required effort to accomplish them. Effort was assessed using time, perceived complexity (with NASA TLX), and eye-tracking data. Participants were more successful in understanding than in reviewing tasks. However, we found no statistically significant difference in the success, time taken, or perceived complexity, between tasks conducted with models with a bad layout and models with a good layout. Most participants had little to no prior knowledge in i*, making them more representative of stakeholders with no requirements engineering expertise. They were able to understand the models fairly well after a short tutorial, but struggled when reviewing models. Adherence to the existing i* layout guidelines did not significantly impact i* model understanding and reviewing performance.

We can regard Domain-Specific Languages (DSLs) as User Interfaces (UIs) because they bridge the gap
between the domain experts and the computation platforms. Usability of DSLs by domain experts is a key
factor for their successful adoption. The few reports supporting improvement claims are persuasive, but
mostly anecdotal. Systematic literature reviews show that evidences on the effects of the introduction of
DSLs are actually very scarce. In particular, the evaluation of usability is often skipped, relaxed, or at
least omitted from papers reporting the development of DSLs. The few exceptions mostly take place at
the end of the development process, when fixing problems is already too expensive. A systematic
approach, based on techniques for the experimental evaluation of UIs, should be used to assess suitability
of new DSLs. This chapter presents a general experimental evaluation model, tailored for DSLs’
experimental evaluation, and instantiates it in several DSL’s evaluation examples.

Objective: To present an overview on the current state of the art concerning metrics-based
quality evaluation of software components and component assemblies.
Method: Comparison of several approaches available in the literature, using a framework
comprising several aspects, such as scope, intent, definition technique, and maturity.
Results: The identification of common shortcomings of current approaches, such as
ambiguity in definition, lack of adequacy of the specifying formalisms and insufficient
validation of current quality models and metrics for software components.
Conclusions: Quality evaluation of components and component-based infrastructures
presents new challenges to the Experimental Software Engineering community.

A rapidly changing market leads to software systems with highly volatile requirements. In many cases, new demands in software can often be met by extending the functionality of systems already in operation. By modularizing volatile requirements that can be altered at the client’s initiative or according to market demands, we can build a stepping-stone for management of requirements change. The volatility must be managed in a way that reduces the time and costs associated with updating a system to meet the new requirements. In this chapter, we present an approach for handling volatile concerns during early life cycle software modeling. The key insight is that techniques for aspect-oriented software development can be applied to modularize volatility and to weave volatile concerns into the base software artifacts.